New Jersey Attorney Paul J. Fishman speaks to the media during a news conference in Newark in July 2013.

Reuters

New Jersey U.S. attorney Paul Fishman has issued a subpoena to a legislative committee investigating the George Washington Bridge closures for its documents pertaining to the matter, a sign that prosecutors are continuing to delve into the issue.

The subpoena was issued by prosecutors for “any and all records” produced or obtained by the New Jersey Legislative Select Committee on Investigation in the course of its work, according to a copy viewed by The Wall Street Journal.

The two-page subpoena was issued last week, and Democratic and Republican members of the committee were made aware of it Thursday night. The records are due back at the U.S. attorney’s office in Newark on May 2, the subpoena states.

A spokeswoman for the U.S. attorney’s office said they don’t comment on the specifics of an investigation.

The committee was formed in January to examine who was responsible for the lane closures that crippled traffic in the borough of Fort Lee, N.J., in September, and why they were conducted. Five allies to Gov. Chris Christie have stepped down since the matter began to come to light last year.

Mr. Christie has said he had no knowledge of the closures, nor would he have condoned them. An internal investigation by lawyers hired by the administration concurred.

The committee and prosecutors are both looking into the matter, and some state lawmakers have questioned the need for the legislative body given Mr. Fishman’s probe. Mr. Fishman’s office and the committee’s counsel, Jenner & Block LLP, have been in touch to discuss their twin probes as they have continued, according to people familiar with the discussions.

The committee has issued more than two dozen subpoenas for records pertaining to the lane closures and has amassed thousands of pages of documents in response.

A new batch of legislative subpoenas issued earlier this week requested testimony from two Christie administration staffers, the executive director of the Port Authority of New York and New Jersey and a commissioner to the agency.

The four individuals are expected to testify before the committee in May.